/Engine/Source/Runtime/RenderCore/Public/RenderGraphBuilder.h
For a graph-created uniform buffer, this forces immediate allocation of the underlying resource, effectively promoting it to an external resource. This will increase memory pressure, but allows access to the RHI resource. Graph resources that are referenced in the buffer will be converted to external. This is primarily used as an aid for porting code incrementally to RDG.
[FRHIUniformBuffer](API\Runtime\RHI\FRHIUniformBuffer) * ConvertToExternalUniformBuffer ( FRDGUniformBufferRef UniformBuffer )